Recirculation helped to establish a stable bacterial community capable of producing bio-hydrogen in reactor RT1. The relatively low pH of 5.5 in the RT1 inhibited the activity of hydrogenotrophic archaea without consuming hydrogen, facilitating high hydrogen production levels. V.For comprehensive estimation of the metal treatment efficiency of bioretention systems, information on metal speciation in the stormwater and the effluent is needed. https://www.selleckchem.com/products/ag-825.html However, so far, most bioretention studies only considered total metal concentrations. Despite their environmental importance, dissolved metals (defined as fractions&nbsp;95%, detailed fractionation revealed that Cu and (when no salt was added) Zn removal in the less then 0.45&nbsp;μm and less then 3&nbsp;kDa fractions was significantly lower. Further, mean concentrations of Cu and (in one treatment) Cd in the less then 0.45&nbsp;μm effluent fraction did not meet Swedish receiving water quality guidelines. By calculating the particulate, colloidal and truly dissolved fractions, it was shown that bioretention systems affect metal speciation of Cu and Zn. Colloidal and truly dissolved fractions were mostly prevalent in the effluent rather than the influent. Salt affected metal removal mostly negatively. Fractionation was affected by salt mainly in the influent where it increased the concentrations of Cd and Zn in the truly dissolved fraction (no effects on Cu and Pb fractions). In the effluent, Cu and Zn were only slightly affected by salt. Vegetation had mostly no significant effects on metal removal and fractionation. Further integration of detailed metal fractionation into sampling routines in bioretention research is recommended. The re-emergence of vanadium (V) as a toxic metal has been highlighted recently due to its long-standing environmental and health hazard. This work targeted the world largest reservoir-Three Gorges Reservoir (TGR) to explore the spatial variation of V in the flooding soils from 2014 to 2018; meanwhile, the typical riparian zones with different altitudes and land-uses at the middle reach of the TGR were selected to decipher the key drivers on the V distribution. The results showed that the concentrations of soil V in the mainstream markedly exceeded local background, but they did not vary significantly with time except a marked increase at the upper-middle reaches. Spatially, the concentrations of soil V increased towards the dam, and the increase trend became increasingly significant with time. At the typical riparian zone, the concentrations of soil V decreased strikingly with altitude despite the difference in the land-uses, and a marked change-point occurred at 160-165&nbsp;m. The soil V dominated by residual fraction, followed by oxidizable and reducible fractions, and then the minimal acid-soluble fraction. The contamination and eco-risk of V in the soils were low with similar spatiotemporal variation to its concentrations. Entrained-sediment flow and particle size rather than pH and organic matters led to the spatiotemporal variation in the distribution of soil V in the mainstream, and the driving effects tended to be more predominant with time. Altitude-regulated alteration of soil properties including particle sizes and iron/manganese (hydr)oxides with different flooding duration dominated the vertical distribution of V over the local land-uses at the riparian zone. Our results reveal the hotspots of V contamination in the riparian soils of the TGR and highlight unceasing focus on the variation in the distribution and dynamic migration of soil V due to its levels out of limits and changing soil conditions. The determinants of intraspecific stoichiometric variation remain difficult to elucidate due to their multiple origins (e.g. genetic vs. environmental) and potential interactive effects. We evaluated whether two size-selected lines of medaka (Oryzias latipes) with contrasted life-history strategies (small- and large-breeder lines with slow growth and early maturity vs. fast growth and late maturity) differed in their organismal stoichiometry (percentage and ratios of carbon [C], nitrogen [N] and phosphorus [P]) in a mesocosm experiment. We also tested how size-selection interacted with environmental conditions (i.e. two levels of fish density and light intensity), body condition and sex. Results showed that large-breeder fish were significantly N-enriched compared to small-breeders, while the two size-selected lines did not differ in body P composition. Size-selection interacted with density - high density only affected small-breeders leading to decreasing %C and C N - and with sex - large-breeder females had higher %C and CN values than large-breeder males. Finally, CP and NP ratios increased with body condition due to decreasing %P. Overall, our results show that the ecological consequences of size-selective mortality extend to organismal stoichiometry and may, from there, change nutrient cycling and ecosystem functioning. The chemical weathering processes become a rising concern in carbon cycling research, because it can increase carbon budgets of lateral transport by rivers and effectively sequestrate atmospheric CO2. Recent studies suggest that the human perturbations can accelerate the chemical weathering, however, the processes of accelerated weathering and its potential environmental effects still remain questions. To examine the mechanism of the human-related accelerated weathering and its influences, the spatial-temporal distributions of the major ions and stable isotope compositions (δ34SSO4) in Jiulongjiang River are measured. The seasonal variations of the riverine solutes results from the hydrologic condition and different mineral dissolution rates of carbonate and silicate minerals. The H2SO4 and HNO3 indeed participate in the mineral dissolution, and increase the riverine C flux. S isotope compositions suggest the riverine H2SO4 is mainly derived from the anthropogenic sewage inputs and oxidation of sulfide, while the statistics and stoichiometry analysis indicating HNO3 are close related to the agricultural activities. On the watershed scale, the areas with high agricultural/urban land use areas (%) have significantly high TDS and DIC values in comparison with that in the areas with high forest covering, indicating the accelerated weathering processes have already been activated by the human perturbations. The assessments of the irrigation water quality suggest that the Jiulongjiang river water is facing the salinity hazard under the accelerated weathering conditions. More attention should be paid to the effect of human perturbations on chemical weathering. V.